The human body maintains a balance between oxidation promoting materials and oxidation inhibiting materials. However, when the body loses this balance and is inclined to a direction to promote oxidation due to various factors, oxidative stress is induced in the body to damage cells and cause pathological diseases. The reactive oxygen species (ROS), which is a direct cause of the oxidative stress, are chemically unstable and highly reactive, and thus they can easily react with various biomaterials (e.g., DNA, proteins, lipids, and carbohydrates) and attack the polymers in the body, thereby causing irreversible damage to cells and tissues or causing mutation, cytotoxicity, cancer, etc.
Meanwhile, macrophages in the human body produce inducers of inflammation (e.g., tumor necrotic factor-α (TNF-α), interleukin-6 (IL-6), interleukin-1β (IL-1β), etc.) by responding to pathogens, and produce nitric oxide (NO) and prostaglandins (prostaglandin E2, PGE2) by synthesizing cyclooxygenase-2 (iNOS) and cyclooxygenase-2 (COX-2). Physiologically, nitric oxide (NO) has various roles in removing bacteria and tumors, regulating blood pressure, mediating neurotransmission, etc. However, when an inflammatory reaction occurs, the expression of iNOS in the related cells increases and thus a large amount of NO is produced, and the excessively produced NO induces tissue damage, gene mutation, nerve damage, etc., and increases vascular permeability to promote inflammatory reactions (e.g., edema, etc.).
When an inflammatory reaction occurs, various free radicals are produced along with various inducers of inflammation. Normal free radicals are involved in the maintenance of cell homeostasis and affect differentiation, growth, survival, and aging of cells. Among these free radicals, reactive oxygen species (ROS) are produced in the mitochondria in a cell through the oxidation and reduction of oxygen by respiration and immune responses. Harmful ROS are generally removed by the actions of anti-oxidant systems (e.g., superoxide dismutase, catalase, glutathione peroxidase, glutamine reductase, vitamin C, vitamin E, uric acid, and bilirubin). However, when the balance between the generation and removal of free radicals collapses, it results in generation of oxidative stress thereby causing various pathological changes (e.g., inflammation, aging, cancer, etc.). In fact, it has been shown that oxidative stress is increased in many clinical diseases, and various studies have been conducted on new anti-oxidants to reduce such oxidative stress.
In this regard, the present inventors have made efforts to discover a novel compound with ensured safety and improved anti-oxidative and anti-inflammatory effects using a safe and effective compound derived from a natural material. As a result, they have confirmed that the compounds which were synthesized using S-allyl-L-cysteine and N-acetyl-L-cysteine as reactants exhibit more excellent safety as well as anti-oxidative and anti-inflammatory activities compared to those of the reactants, thereby completing the present invention.